diff --git a/model/ability.go b/model/ability.go
index 5679b61..0e5eb2c 100644
--- a/model/ability.go
+++ b/model/ability.go
@@ -6,8 +6,8 @@ import (
 )
 
 type Ability struct {
-	Group     string `json:"group" gorm:"type:varchar(255);primaryKey;autoIncrement:false"`
-	Model     string `json:"model" gorm:"primaryKey;autoIncrement:false"`
+	Group     string `json:"group" gorm:"type:varchar(64);primaryKey;autoIncrement:false"`
+	Model     string `json:"model" gorm:"type:varchar(64);primaryKey;autoIncrement:false"`
 	ChannelId int    `json:"channel_id" gorm:"primaryKey;autoIncrement:false;index"`
 	Enabled   bool   `json:"enabled"`
 	Priority  *int64 `json:"priority" gorm:"bigint;default:0;index"`
diff --git a/model/channel.go b/model/channel.go
index 7cdc2f6..96b3635 100644
--- a/model/channel.go
+++ b/model/channel.go
@@ -21,7 +21,7 @@ type Channel struct {
 	Balance            float64 `json:"balance"` // in USD
 	BalanceUpdatedTime int64   `json:"balance_updated_time" gorm:"bigint"`
 	Models             string  `json:"models"`
-	Group              string  `json:"group" gorm:"type:varchar(255);default:'default'"`
+	Group              string  `json:"group" gorm:"type:varchar(64);default:'default'"`
 	UsedQuota          int64   `json:"used_quota" gorm:"bigint;default:0"`
 	ModelMapping       *string `json:"model_mapping" gorm:"type:varchar(1024);default:''"`
 	Priority           *int64  `json:"priority" gorm:"bigint;default:0"`